Over 400 years ago, the bark of the cinchona tree was discovered to contain a chemical compound called quinine. Quinine was, and still is, used to cure and prevent malaria. This is an early example of . a. biotechnology

b. scientific modeling

c. genetic engineering

d. genomics

Vegetation that grows along the floors of tropical and temperate forests is called undergrowth. how is the undergrowth of a tropical rain forest most likely to differ from the undergrowth of a temperate forest? a. a tropical rain forest's undergrowth most likely experiences periods of dormancy during colder weather. b. a tropical rain forest's undergrowth most likely experiences periods of dormancy during rainy weather. c. the undergrowth of a tropical rain forest most likely requires less sunlight. d. the undergrowth of a tropical rain forest most likely requires more sunlight.

Which best describes how the common cold spreads in the human body? a bacteria burst out of normal cells killing them b viruses replicate inside respiratory cells c bacteria inject dna into normal cells d viruses insert dna into bacteria

Idon’t know the answer and i’ve been stuck on it for a while now skskskskks